Apparatus and methods for the control of hydraulic actuators

Abstract

Methods of controlling an actuator during operation using a hydraulic circuit, and related apparatus, are described. The circuit has a first path section along which fluid is supplied to a first chamber of the actuator using a first valve and a second path section along which fluid is extracted from a second chamber of the actuator using a second valve. Pressure data associated with a pressure of the fluid supplied to the first side of the actuator are obtained, a pilot pressure pPilot is produced based on the data and the first and second valves are configured based on the pilot pressure pPilot.

The invention claimed is: 
     
       1. A method of controlling an actuator during operation using a hydraulic circuit, the circuit comprising a pressure compensating valve, a counterbalance valve, a load-sensing directional control valve, a first path section along which a hydraulic fluid is supplied to a first chamber of the actuator via the pressure compensating valve, the hydraulic fluid being supplied to the first chamber via the load-sensing directional control valve, and a second path section along which the hydraulic fluid is extracted from a second chamber of the actuator via the counterbalance valve, the method comprising the steps of:
 (a) obtaining pressure data associated with a pressure of the hydraulic fluid supplied to a first side of the actuator; 
 (b) producing a pilot pressure pPilot in a control fluid based on the pressure data; 
 (c) configuring the pressure compensating valve using the pilot pressure pPilot; and 
 (d) configuring the counterbalance valve using the pilot pressure pPilot. 
 
     
     
       2. A method as claimed in  claim 1 , wherein the pressure data comprises a signal of the pressure in the hydraulic fluid supplied to the first chamber. 
     
     
       3. A method as claimed in  claim 1 , wherein the obtained pressure data are first pressure data, and the method further comprises processing the first pressure data to produce second pressure data, wherein the pilot pressure pPilot is produced based upon the second pressure data. 
     
     
       4. A method as claimed in  claim 3 , wherein at least one component from the first pressure data is preserved in the produced second pressure data. 
     
     
       5. A method as claimed in  claim 3 , wherein the step of processing the first pressure data to obtain the second pressure data comprises filtering the first pressure data. 
     
     
       6. A method as claimed in  claim 5 , wherein the step of filtering comprises applying a low-pass filter to the first pressure data. 
     
     
       7. A method as claimed in  claim 3 , which further comprises generating a control signal uProp based on the second pressure data, and passing the control signal uProp to a first valve to produce the pilot pressure pPilot for configuring both of the pressure compensating valve and the counterbalance valve. 
     
     
       8. A method as claimed in  claim 7 , wherein the first valve is operable to configure a valve control path for adjusting a pressure in the control fluid in the path. 
     
     
       9. A method as claimed in  claim 7 , which further comprises measuring the produced pilot pressure pPilot, comparing the measured pilot pressure with the second pressure data, and updating the control signal uProp in dependence upon the comparison. 
     
     
       10. A method as claimed in  claim 1 , wherein the obtained pressure data are first pressure data, and the method further comprises processing the first pressure data to determine at least one set pressure pSet for determining the pilot pressure pPilot. 
     
     
       11. A method as claimed in  claim 1 , wherein the pressure compensating valve is operable for adjusting a pressure of the fluid in the first path section. 
     
     
       12. A method as claimed in  claim 1 , wherein the counterbalance valve is operable for resisting undesired movement of the actuator. 
     
     
       13. A method as claimed in  claim 1 , wherein the pressure compensating valve and the counterbalance valve are configured to be operable to maintain an actuator speed that is independent of external disturbances on the actuator. 
     
     
       14. A method as claimed in  claim 1 , wherein the first path section comprises a metering-in line. 
     
     
       15. A method as claimed in  claim 1 , wherein pressure data associated with the pressure in the hydraulic fluid supplied to the first side of the actuator comprises at least one pressure pLS of the hydraulic fluid at an outlet of a load sensing directional control valve. 
     
     
       16. A method as claimed in  claim 1 , wherein the pressure compensating valve is positioned upstream of the load-sensing directional control valve. 
     
     
       17. Apparatus for operating and controlling a hydraulic actuator, the apparatus comprising:
 a pressure compensating valve and a counterbalance valve; 
 a first path section along which a hydraulic fluid is supplied to a first chamber of the actuator using the pressure compensating valve; 
 a second path section along which the hydraulic fluid is extracted from a second chamber of the actuator using the counterbalance valve; 
 a load-sensing directional control valve wherein the hydraulic fluid is supplied to the first chamber via the load-sensing directional control valve; and 
 at least one device for producing a pilot pressure pPilot in a control fluid based upon obtained data associated with a pressure of the hydraulic fluid supplied to the first chamber of the actuator, wherein both of the pressure compensating valve and the counterbalance valve are configured using the pilot pressure pPilot. 
 
     
     
       18. Apparatus as claimed in  claim 17 , further comprising the actuator. 
     
     
       19. Apparatus as claimed in  claim 17 , wherein said at least one device comprises any one or more of: a determiner; a controller; and a control structure. 
     
     
       20. Apparatus as claimed in  claim 17 , further comprising a control fluid circuit, or components thereof, for controlling both of the pressure compensating valve and the counterbalance valve. 
     
     
       21. Apparatus as claimed in  claim 17  further comprising a computer device configured to receive data associated with a pressure of the hydraulic fluid supplied to the first chamber of the actuator, for determining a pilot pressure pPilot to be generated based upon the obtained data for configuring both of the pressure compensating valve and the counterbalance valve. 
     
     
       22. Apparatus as claimed in  claim 17 , wherein:
 the pressure compensating valve is operable for adjusting a pressure of the hydraulic fluid in the first path section; and 
 the counterbalance valve is operable for resisting undesired movement of the actuator. 
 
     
     
       23. Apparatus as claimed in  claim 17 , wherein the pressure compensating valve is positioned upstream of the load-sensing directional control valve. 
     
     
       24. A non-transitory machine-readable storage medium encoded with instructions executable by a processor for controlling an actuator using a hydraulic circuit, the hydraulic circuit comprising a first path section along which a hydraulic fluid is supplied to a first chamber of the actuator using a pressure compensating valve, and a second path section along which the hydraulic fluid is extracted from a second chamber of the actuator using a counterbalance valve, hydraulic circuit further comprising a load-sensing directional control valve, the hydraulic fluid being supplied to the first chamber via the load-sensing directional control valve, the machine-readable storage medium comprising:
 instructions to receive data associated with a pressure of the hydraulic fluid supplied to the first chamber of the actuator; 
 instructions to determine a pilot pressure pPilot in a control fluid based upon the received data; 
 
       instructions to configure both of the pressure compensating valve and the counterbalance valve using the pilot pressure pPilot. 
     
     
       25. Non-transitory machine-readable storage medium as claimed in  claim 24 , wherein:
 the pressure compensating valve is operable for adjusting a pressure of the hydraulic fluid in the first path section; and 
 the counterbalance valve is operable for resisting undesired movement of the actuator. 
 
     
     
       26. A method of controlling an actuator during operation using a hydraulic circuit comprising a first path section along which a hydraulic fluid is supplied to a first chamber of the actuator using a pressure compensating valve, and a second path section along which the hydraulic fluid is extracted from a second chamber of the actuator using a counterbalance valve, the hydraulic circuit further comprising a load-sensing directional control valve, the hydraulic fluid being supplied to the first chamber via the load-sensing directional control valve, the method comprising the steps of:
 (a) computing a set pressure pSet in a control fluid in dependence upon a pressure of the hydraulic fluid supplied to the first chamber of the actuator; and 
 (b) configuring both of the pressure compensating valve and the counterbalance valve based on the computed set pressure. 
 
     
     
       27. A method as claimed in  claim 26 , wherein:
 the pressure compensating valve is operable for adjusting a pressure of the hydraulic fluid in the first path section; and 
 the counterbalance valve is operable for resisting undesired movement of the actuator.